Checkerboard patterns of bone, ebony, and fruitwood decorate the back, sides, and neck of Ertel's guitar. The peghead, fingerboard, and top have inlaid ornaments of mother-of-pearl. The modern rosette of wood and parchment is a replacement. Formerly converted to six single strings, this instrument was later restored to its five-course configuration. A similar signed instrument is in the Innsbruck Landesmuseum.